The letter was from a woman who claimed that Hall, now 83, visited her school when she was a “young teenager” in the 1970s and later groomed her for sex.

Columnist Yasmin Alibhai-Brown was given the letter and decided to hand it in to her local police station at Ealing.

She writes today in today's Independent: “A few weeks later I had a call from Detective Constable Rukin of Lancashire Police. Officers wanted to come over to interview me. Hall had not been on their 'radar' but after the letter forwarded by Ealing Police, a line of inquiry had been opened.”

Alibhai-Brown said that last Thursday she was told by DC Rukin “had they not been sent this letter, Hall would never have been investigated".

“I believe they have now interviewed the woman who wrote to me. I hope she was one of the girls Hall now accepts he did abuse.

“She will, I hope, now at last find some peace. She should be so very proud that decades after being entrapped and abused by a manipulative man, she was able to express her anger, hurt, sense of guilt and betrayal so honestly to a stranger….

“Finally, I know we journalists are thought heartless by millions of Britons. But it is heartening that there are readers who trust us. Most of us try hard not to break the faith they have in us.”